Alternative Werkstoffe für Komponenten der Hochtemperatur-Brennstoffzelle (SOFC) zur Herabsetzung der Betriebstemperaturen

Ahmad-Khanlou, Ariane

Book	PreJuSER-45757

Alternative Werkstoffe für Komponenten der Hochtemperatur-Brennstoffzelle (SOFC) zur Herabsetzung der Betriebstemperaturen

Ahmad-Khanlou, A. (Corresponding author)FZJ*

2000
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Jülich : Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag, Berichte des Forschungszentrums Jülich 3797, 123 p. (2000)

Please use a persistent id in citations: http://hdl.handle.net/2128/20624

Report No.: Juel-3797

Abstract: Components of the solid oxide tuet cell (SOFC) are exposed to temperatures > 1200 °C during fabrication. Moreover, they must withstand the operating temperatures of about 850 °C for operating times of more than 40,000 hours. Any interdiffusion processes occurring or the formation of reaction products can impair performance efficiency and service He. A reduction of the fabrication and operating temperatures should therefore be aimed at . Since the electrolyte of yttria-stabiiized zirconla (YSZ) available at present only exhibits a sufficiently high ionic conductivity at temperatures above 800 °C, the development of alternative membrane materials is required which must also guarantee high performance stability at reduced operating temperatures . In parallel to this, efforts are being made to enhance the SOFC performance by optimizing the cathode compounds already available . These alternative compounds must satisfy a number of further requirements in addition to high chemical stability . They must display e .g. a thermal expansion coefficient adapted to the other SOFC components for thermal cycling, excellent transport properties as well as high catalytic activity. For application as the electrolyte membrane, the Lao .gSro.IGaase Mg0203 tx and LaosSro.2Gao*9Mg0 .103_x gallates were characterized in detail in this work . A single-phased nature difficult to establish, the tendency to Ga evaporation under oxidizing as well as reducing conditions and strong interactions with the electrode materials are decisive criteria for the inapplicability of these compounds in SOFCs . On the cathode side, substoichiometric perovskites based an LnMn03 and LaFeO3 (with Ln lanthanides) were primarily examined . By selectively substituting these systems with strontium and cobalt it was intended to improve the material properties . A systematic characterization of these compounds with respect to phase purity, thermal expansion coefficient, electrical and ionic conductivity served to evaluate their applicability . Furthermore, investigations into chemical interactions with the standard YSZ electrolyte contributed towards selecting a number of suitable cathode materials which also had to prove efficient in electrochemical single-cell measurements . Apart from La0.65Sr0 33MnO3, which is used as the standard cathode material at Research Centre Jülich, the compounds Pro.65Sro,3MnO3 and PrO. 75.Sr02Mn0 88C00.2O3 may be considered as promising candidates enabling a reduction of the fabrication and operating temperatures

Note: Record converted from VDB: 12.11.2012

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